VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 1925 Engine Questions

Hello,
I recently picked up a chassis with engine that I believe to be 1925. The casting date year digit on the engine is hard to make out. Either 5 or 6. I thought 6 at first but it's the type of engine with the generator, distributor, oil pump combined. The oil pump has three pipe connections. The rear hubs are four bolt. The front are six. Unfortunately, the oil pump and the cap rim on the distributor appear to be suffering from the dreaded pot metal disease. They are all there but lots of cracks and separation. The pot metal piece at the base of the transmission shift lever is mostly gone. What is the prevailing wisdom when working on these parts? Are replacements available or do most just try to find original parts in workable condition? Worst case, use as-is? I relate to my prior experience of trying to find a wiper motor for a 28 closed car. They just didn't survive.

Thanks!
-R

Hi RustyFender,

Based on your description and assumed date it is fairly certain that you have a 1925 engine. If the valve covers are present and there are two of them we are on track.

The rear hub with the 4-bolt pattern is for sure 1925. My guess is that the front ones are a transplant.

Your concerns about the pot metal items, oil pump, rear generator plate, and distributor are valid concerns, however each item is now available as replacement parts.

Most hard parts are available for the early cars, it is the sheet metal that is difficult to locate and almost impossible to find in useable condition is any of the aluminum radiator shells.

The top cover for the transmission shift lever is also available now.

You should find a date on the head also. If you remove the exhaust manifold it is likely you will find the block/engine serial number stamped in the edge of the exhaust port.

Thanks Ray,
Yes, the valve covers are present and there are two of them. It looks as if someone has taken two six lug wheels and drilled them for use on a four lug hub out back. I can see the unused holes around the trim ring. The aluminum radiator shell is no good. The water outlet from the bottom tank of the radiator has broken off up against the tank leaving a big rectangular hole. What's left is hanging from the lower radiator hose. Maybe it can be soldered by a professional, maybe not. The condition of the honeycomb core is unknown. Are the 25 radiator shells interchangeable with any other years? 26, 27? Also, the engine has a modelA carb on it. What was correct for 25? I have a rebuilt RXO on the shelf.

Thanks!
Ron

Hi Ron,

The 1925 and 26 share the same shell. The fellow who was making them has long since grew too elderly to continue. Business turned over to son who has other interests.

Perhaps the best we can do now is accept the steel shells that were used on the commercials and have them nickle plated.

At one time I was told that there is a space age process to coat the steel with aluminum. Probably so and the cost would also be space age.

The bottom and top tank can be removed and a new honeycomb core from the Filling Station installed. The loose bottom outlet is not a problem.

The correct carburetor is the RXO. Lucky you.

Ray you've raised a question in my mind. When did Chevrolet go to a single valve cover? My '26 sedan (late '25 K -- built Oct. '25 ) has a one piece valve cover. Do you know if they started this change in August of '25 or did it start with the "V" series engine?

When they removed the gear drive generator and went to the belt drive, the cover was changed to a single at that time.

The gear drive is the K and the belt drive is the V.

OK Ray..Thank you; Now I'll have to keep an eye open for a pair of those short valve covers.

Just sold my last pair about two weeks ago.

If you cannot make out the date code, do you have the ENGINE #! Also the casting codes on Block and Heads?